How Are Hormone Levels Regulated

Multiple Choice

How are hormone levels regulated?

A) An endocrine gland can respond to the blood level of the hormone it produces.
B) A hormone can trigger a second gland to secrete a hormone that dampens production of the first hormone.
C) A second contrary hormone can counteract the effect of the first hormone.
D) A product can trigger hormone production; the hormone can then reduce the amount of product which in turn reduces the level of hormone.
E) All of the choices are correct.